Semiconductor device and manufacturing method thereof

Abstract

A semiconductor device includes groove-like regions that are formed between two adjacent bit lines among a plurality of bit lines each having upper and side surfaces covered with a cap insulating film and a side-wall insulating film, respectively, a SiON film that contains more O (oxygen) than N (nitrogen) and continuously covers inner surfaces of the groove-like regions, and a silicon dioxide film formed by reforming polysilazane and filled in the groove-like regions with the SiON film interposed therebetween.

What is claimed is: 
     
       1. A semiconductor device comprising:
 a plurality of groove-like regions formed between adjacent bit lines on a second interlayer insulating film; 
 said bit lines having upper surfaces covered with a cap insulating film, and side surfaces covered by a side wall insulating film; 
 a SiON film that contains more O (oxygen) than N (nitrogen) and continuously covers upper surfaces of the cap insulating film and outer surfaces of the side wall insulating film and also covering parts of an upper surface of the second interlayer insulating film; and 
 a silicon dioxide film that is formed by reforming polysilazane and is filled in the groove-like regions with the SiON film interposed therebetween. 
 
     
     
       2. The semiconductor device as claimed in  claim 1 , wherein a content rate of the N in the SiON film is 10 to 20 atom %. 
     
     
       3. The semiconductor device as claimed in  claim 1 , wherein a ratio in atom number of the O to the N in the SiON film is 2.2 to 5.5. 
     
     
       4. A semiconductor device comprising:
 a plurality of groove-like regions formed between adjacent bit lines; 
 said bit lines having upper side surfaces covered with a cap insulating film, and side surfaces covered by a side wall insulating film; 
 a SiON film that contains more O (oxygen) than N (nitrogen) and continuously covers upper surfaces of the cap insulating film and outer surfaces of the side wall insulating film and also covering parts of an upper surface of a transistor device region of a memory cell in the semiconductor device; and 
 a silicon dioxide film that is formed by reforming polysilazane and is filled in the groove-like regions with the SiON film interposed therebetween. 
 
     
     
       5. The semiconductor device as claimed in  claim 4 , wherein a cell contact extends within a groove-like region of the plurality of groove-like regions and contacts the transistor device region below the SiON film, and the SiON film prevents shorting between transistor device regions aligned with groove-like regions in which no cell contact extends.